Our "Why do they call it that?" series continues its month-long Military May with a teenager's heroic sacrifice in the waters of Tampa Bay.

Why do they call it the Coast Guard Cutter William Flores?

As one of the U.S. Coast Guard's newest big ships -- called cutters -- the William Flores has higher top speeds and more advanced technology than the rest.

It's a tremendous tool for stopping drug runners and rescuing people stranded at sea. But while the technology's impressive, it's the name of the ship that's truly inspiring.

The namesake of U.S. Coast Guard Cutter William Flores is a young hero, Billy Flores. He was just 18 years old -- less than a year out of boot camp -- when he was serving on board the Coast Guard Cutter Blackthorn in 1980.

About three-quarters of a mile south of the Sunshine Skyway Bridge, the Blackthorn collided with an oil tanker. Within minutes, the Blackthorn sank in what's called the worst peacetime disaster in the Coast Guard's history.

Seaman Apprentice Billy Flores -- again, just a teenager -- had access to a life vest. Instead of putting it on, he threw it to a shipmate who was struggling in the water.

The ship was twisting on its side and clearly going down quickly. Flores raced to the locker where the life jackets are kept.

He took his belt and used it to tie open the door to the locker so the life vests would float to the surface as the ship sank.

Instead of abandoning ship, Flores stayed on board as the Blackthorn took on water, helping injured crew members get out from inside the ship.

Billy Flores' heroism, along with other brave acts by his shipmates, saved 27 people. But 23 other people lost their lives as the Blackthorn sank -- including young Billy Flores.

To honor Flores, the new ship -- one of the first in the cutting-edge Sentinel class -- bears his name.

Why do they call it that? Now you know.

We feature new "Why do they call it that?" stories each Wednesday on 10 News starting at 5 a.m. and 5 p.m.